This is the slickest multi-tune option out there for the
tuners of most OBD1 vehicles. Most 1985 - 1995
GM models, 1986 - 1995 Nissan models, 1990- 1994 Mitsubishi
1G models with eprom ECMs or eprom ECM conversions, and 1988 - 1995 Honda
and Acura models utilized 28 pin 8 bit memory devices like
the 27c128, 27c256, or 27c512.
The Multi-tune Adapter installs into the standard 28 pin ROM socket of your
Engine Management Computer, memcal or other memory adapter--anyplace
you would plug in a 27C128, 27c256, or 27c512 ROM. It
allows the use of a 512k ROM (most commonly a 27sf512 these
days) and has
a power input which will switch between the upper and lower
half of the 512k ROM. This allows you to have two
versions of software installed and to switch between them on
the fly.
The switching is invisible to the engine
management computer and because it uses a power input to
initiate the switch it can be controlled by another
electronic device as well as a simple manual switch.
Common uses are to tune for multiple types of fuels, connect
to boost controllers to allow special tuning at different
boost levels, or to wire to nitrous oxide relays to offer
all your engine control unit's power to you for tuning your
nitrous shot. Wired to your nitrous relays it
will instantaneously switch to your 2nd tune when your
relays open allowing you to put all your fuel in through
your injectors or just fine tune your afr with your wet
shot, customize your ignition timing, etc., etc.
This is the way to do nitrous right.
Multi-tune information page.

If you love your SVX you'll truly love this photo album.
You're likely to see photos of things you never knew have
been accomplished. 165 HP nitrous systems, custom
pistons for high compression race cars, custom pistons for
high boost turbo cars, racing engine builds, dyno testing, conversions to JDM drivelines, transmission
modifications, and more. I'm a true SVX enthusiast.
I had big dreams for her from the moment I purchased my
first SVX over ten years ago, a south Florida car that's
never seen salt, snow, or a fender bender. Back then
there were no performance chips, there was no ability to
download the firmware off the control units, none of the
information necessary to order performance engine
parts had been measured or published, nobody had figured out
the weak links of the transmission or developed power packs
or through bolted drive gears. I had to develop all of
these things from scratch to make my dreams come true.
Here are some pictures from along the way.

We have designed an interface cable and Windows
application which allows us to communicate with Subaru
control units. This allows us to perform all the same
diagnostics as the dealer's diagnostic equipment, the Subaru
Select Monitor. It also allows us to download the
firmware off of Subaru control units. We will be
releasing a version for your personal use at home soon.